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    <title>Document</title>
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    <script>
        const fn = () => {
            console.log(123)
        }

        const sum = (num1,num2) => num1+num2/* 函数体只有一句代码，且返回值就是它 */

        const fnv = v =>{/* 形参只有一个时，可以省略小括号 */
            console.log(v);
        }



        fn()
        console.log(sum(4,5));
        fnv(20)
    </script>
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